(1) Field of the Invention
This invention relates to an apparatus for liquefying refrigerant and generating a low temperature state in which the adiabatic expansion of refrigerant is utilized for providing a low temperature state.
(2) Description of the Prior Art
There are many fields requiring low temperatures as in industrial processes such as refrigeration, cold storage, air conditioning. In this connection, a so-called compression type refrigerator is extensively employed in which a refrigerant circulating cycle consisting of compression, condensation, expansion and evaporation is effected to provide a low temperature. However, it should be noted that in the refrigerator of this type a considerably high pressure is developed during the compression; and accordingly the refrigerator suffers from disadvantages that it must have a mechanical strength strong enough to withstand the high pressure, which leads to increase in size of the refrigerator and to increase in manufacturing cost thereof. In addition, the large noise of the compressor is another problem to be solved.